The present invention relates generally to an ion exchange membrane electrolyzer, and more particularly to an ion exchange membrane electrolyzer that can space electrodes away from each other at a given spacing.
In an electrolyzer used for electrolysis of an aqueous solution, the voltage required for electrolysis depends on various factors. In particular, the anode-to-cathode spacing has some considerable influences on electrolyzer voltage. One conventional approach to keeping the energy consumption necessary for electrolysis low is to cut down the spacing between electrodes, thereby dropping electrolyzer voltage.
In an ion exchange membrane electrolyzer or the like used for electrolysis of brine, three members, i.e., an anode, an ion exchange membrane and a cathode are located in a close contact manner to lower electrolyzer voltage. For a large electrolyzer having an electrode area of as large as a few square meters, wherein the anode and cathode are coupled to the respective chambers by means of rigid members, however, it is still difficult to bring both the electrodes in close contact with the ion exchange membrane, thereby cutting down the inter-electrode distance and keeping it at a given small value.
To solve this problem, an electrolyzer has been proposed, wherein a flexible member is used for at least one of the anode and cathode thereby making the inter-electrode spacing adjustable.
Various electrolyzers using flexible members as the means for cutting down the inter-electrode spacing have been proposed in the art, and electrodes with a flexible member located on an electrode substrate have been put forward as well, said flexible member comprising woven fabrics, non-woven fabrics, networks or the like fabricated of small-gauge metal wires.
These electrodes have flexible members formed of small-gauge metal wires, and so problems therewith are that when the electrode is excessively forced by reverse pressure from the opposite electrode, it is partly deformed resulting in an uneven inter-electrode spacing or the small-gauge wires are impaled into the ion exchange membrane.
An electrolyzer wherein an electrical connection is made between an electrode chamber partition and an electrode by means of a number of flat leaf spring members has been proposed in JP(A)57-108278 and JP(A)58-37183.
FIGS. 10(A), 10(B) and 10(C) are illustrative of a prior art electrolyzer comprising a flat leaf spring member.
FIG. 10(A) is a partly sectioned view of a conventional ion exchange membrane electrolyzer using a flat leaf spring member; FIG. 10(B) is a plan view of the flat leaf spring member; and FIG. 10(C) is a sectional view of that flat leaf spring member.
In an electrolyzer 51, an anode rib 56 and a cathode rib 57 are joined to an anode chamber partition 55 for an anode chamber 52 and a cathode chamber partition 54 for a cathode chamber 53 at a given spacing, respectively. An anode mount substrate 58 is attached to the anode rib 56, and an anode 59 is attached to the anode mount substrate 58.
The cathode rib 57 is provided with a cathode retainer member 61 having a number of flat leaf spring tabs 60 to retain a cathode 62 by the flat leaf spring tabs 60. Accordingly, even when the inter-electrode spacing is cut down, it is unlikely that large force is applied to an ion exchange membrane 63 between the anode 59 and the cathode 62.
Flexible electrodes using flat leaf spring tabs are superior to those using small-gauge wire members or the like in terms of behavior leading to partial deformation upon forced; however, all such flat leaf spring tabs in these electrolyzers extend from a flexible cathode retainer member at an angle in the same direction.
Upon the application of force from an electrode surface side, the force acts on the electrode surface to cause displacements of the flat leaf spring tags and move them in one direction along which the spring material is deformed, possibly resulting in misalignment of the flat leaf spring tags with the electrode, and damage to an ion exchange membrane upon such electrode misalignment when the electrode is in contact with the ion exchange membrane.
The present invention relates to an electrolyzer in which electrodes and a collector are coupled together by flexible electric current feeding means. A primary object of the present invention is to provide an electrolyzer in which even an electrode surface having a large area is smoothly retained to prevent displacement of the electrode in any direction by flexible electric current feeding means or application of excessive pressure on an ion exchange membrane surface in the case of an ion exchange membrane electrolyzer.